Compressing and decompressing signal data

ABSTRACT

The present invention relates to data compression and decompression, and particularly relates to a method and an apparatus for compressing and decompressing signal data. In an embodiment of the present invention, there is disclosed a method for compressing signal data, comprising: obtaining signal data; determining block lengths of a plurality of data blocks into which the signal data are divided, and determining exponents of the data blocks; forming a mantissa sequence of the data block by using the exponent of the data block to compress signal data contained in the data block; and forming a compressed data block by using the block length, the exponent and the mantissa sequence of the data block. By constructing a variable-length data block adapted to dynamic characteristics of signal data, the method for compressing signal data of the present invention increases the compression ratio of signal data.

PRIORITY

This application claims priority to Chinese Patent Application No.201210177519.8, filed May 31, 2012, and all the benefits accruingtherefrom under 35 U.S.C. §119, the contents of which in its entiretyare herein incorporated by reference.

BACKGROUND

The present invention relates to data compression and decompression, andmore specifically, to methods and apparatuses for compressing anddecompressing signal data.

In the field of wireless signal processing, e.g., in a base transceiversystem or an information acquisition and processing system, a signal istypically modulated into two orthogonal data branches, i.e. I and Q databranches, and in a digital signal processor, the two data branches I andQ are usually represented by fixed-length fixed-point numbers (taking a16-bit analog-to-digital converter as an example, if an analog signal isinputted, outputted two data branches I and Q are both 16-bit binaryfixed-point numbers). These I/Q data have the following characteristics:

(1) A relatively larger set of data. Taking 16-bit I/Q data as anexample, a size of the data set is 2¹⁶.

(2) Relatively low percentage of occurrences frequency of a singlenumeric value, which is usually lower than 1%.

(3) Close value ranges of consecutive data. Taking 16-bit I/Q data as anexample, several consecutive data might fall within a range of [2⁶, 2⁷).

Compression of I/Q signal data with the foregoing characteristicsenables more efficient use of resources. Specifically, in a basetransceiver system, a compressor performs compression to signal datawhereby the amount of signal data in transmission links can be reducedand thus the bandwidth can be saved; in an information acquisition andprocessing system, a compressor performs compression to signal datawhereby the amount of signal data to be stored can be reduced and thusthe capacity of storage devices can be saved.

However, traditional data compression methods based on informationentropy theory, either statistics-based Huffman coding and arithmeticcoding, or dictionary-based compression methods (like LZW), are far fromsatisfactory in terms of compression complexity, decompressioncomplexity and compression efficiency. “A relatively larger set of data”means maintaining and storing a relatively larger table, which makes thecompression complexity and decompression complexity relatively high;“relatively low percentage of occurrences frequency of a single numericvalue” implies relatively bad compression efficiency.

Therefore, there is a need for a high-efficiency compression method forsignal data.

SUMMARY

In one embodiment, a method for compressing signal data includesobtaining signal data; determining block lengths of a plurality of datablocks into which the signal data are divided, and determining exponentsof the data blocks; forming a mantissa sequence of the data block byusing the exponent of the data block to compress signal data containedin the data block; and forming a compressed data block by using theblock length, the exponent and the mantissa sequence of the data block.

In another embodiment, a method for decompressing compressed signaldata, includes obtaining compressed signal data; obtaining a blocklength and an exponent of a data block from the compressed signal data;obtaining a mantissa sequence of the data block according to the blocklength and the exponent of the data block; and restoring original signaldata corresponding to the data block by using the mantissa sequence andthe exponent.

In another embodiment, an apparatus for compressing signal data,includes an obtainment module configured to obtain signal data; a blocklength and exponent determination module configured to determine blocklengths of a plurality of data blocks into which the signal data aredivided, and determine exponents of the data blocks; a mantissa sequenceformation module configured to form a mantissa sequence of the datablock by using the exponent of the data block to compress signal datacontained in the data block; and a compressed data block formationmodule configured to form a compressed data block by using the blocklength, the exponent and the mantissa sequence of the data block.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The above and other objects, features and advantages of the presentdisclosure will become more apparent through the more detaileddescription of exemplary embodiments of the present disclosure inconjunction with the accompanying drawings in which like referencenumbers generally refer to like components in the embodiments of thepresent disclosure.

FIG. 1 shows an exemplary computer system which is applicable toimplement an embodiment of the present invention;

FIG. 2 shows a block diagram of a base transceiver system according toan embodiment of the present invention;

FIG. 3 shows a block diagram of an information acquisition andprocessing system according to an embodiment of the present invention;

FIG. 4 shows a method for compressing signal data according to anembodiment of the present invention;

FIG. 5 shows a flowchart of determining block lengths of a plurality ofdata blocks into which the signal data are divided and exponents of thedata blocks according to an embodiment of the present invention;

FIG. 6 shows a flowchart of determining block lengths of a plurality ofdata blocks into which the signal data are divided and exponents of thedata blocks according to another embodiment of the present invention;

FIG. 7 shows an example of generating a mantissa sequence and acompressed data block according to an embodiment of the presentinvention;

FIG. 8 shows a method for decompressing compressed signal data accordingto an embodiment of the present invention;

FIG. 9 shows an apparatus for compressing signal data according to anembodiment of the present invention; and

FIG. 10 shows an apparatus for decompressing signal data according to anembodiment of the present invention.

DETAILED DESCRIPTION

Some exemplary embodiments of the present disclosure will be describedin more detail with reference to the accompanying drawings. Theexemplary embodiments of the present disclosure have been illustrated inthe accompanying drawings; however it should be appreciated that thepresent disclosure can be implemented in various manners, and is notlimited to the embodiments disclosed herein. On the contrary, thoseembodiments are provided for the thorough and complete understanding ofthe present disclosure, and completely conveying the scope of thepresent disclosure to those skilled in the art.

By constructing a variable-length data block adapted to dynamiccharacteristics of signal data, a method for compressing signal dataaccording to the embodiments of the present invention makes compressionof signal data have robustness, thereby increasing the compression ratioof signal data.

FIG. 1 shows a block diagram of an exemplary computer system 100 whichcan be used to implement the embodiments of the present invention. Asshown in FIG. 1, the computer system 100 may include: CPU (CentralProcess Unit) 101, RAM (Random Access Memory) 102, ROM (Read OnlyMemory) 103, System Bus 104, Hard Drive Controller 105, KeyboardController 106, Serial Interface Controller 107, Parallel InterfaceController 108, Display Controller 109, Hard Drive 110, Keyboard 111,Serial Peripheral Device 112, Parallel Peripheral Device 113 and Display114. Among above devices, CPU 101, RAM 102, ROM 103, Hard DriveController 105, Keyboard Controller 106, Serial Interface Controller107, Parallel Interface Controller 108 and Display Controller 109 arecoupled to the System Bus 104. Hard Drive 110 is coupled to Hard DriveController 105. Keyboard 111 is coupled to Keyboard Controller 106.Serial Peripheral Device 112 is coupled to Serial Interface Controller107. Parallel Peripheral Device 113 is coupled to Parallel InterfaceController 108. In addition, Display 114 is coupled to DisplayController 109. It should be understood that the structure as shown inFIG. 1 is only for the exemplary purpose rather than any limitation tothe present invention. In some cases, some devices may be added to orremoved from the computer system 100 as required by specific situations.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining of software and hardware, aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program codes embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination thereof. More specificexamples (a non-exhaustive list) of the computer readable storage mediumwould include: an electrical connection having one or more wires, aportable computer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), an optical fiber, a portable compact disc read-onlymemory (CD-ROM), an optical storage device, a magnetic storage device,or any suitable combination of the foregoing. In the context of thisdocument, a computer readable storage medium may be any tangible mediumthat can contain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention will be described below with referenceto flowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchart and/orblock diagrams, and combinations of blocks in the flowchart and/or blockdiagrams, can be implemented by computer program instructions. Thesecomputer program instructions may be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/operations specified in the flowchart and/orblock diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions meansfor implementing the functions/operations specified in the flowchartand/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational to be performed on the computer, otherprogrammable data processing apparatus or other devices to produce acomputer implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/operations specified in the flowcharts and/orblock diagram block or blocks.

FIG. 2 shows a block diagram of a base transceiver system according toan embodiment of the present invention. For the uplink, a receiver in aradio remote unit receives a signal from an antenna, the signal isconverted into signal data via an analog-to-digital converter, thesignal data is compressed by a compressor and is sent to a baseband unitover a data transmission link, the compressed signal data isdecompressed by a decompressor in the baseband unit, and finally thedecompressed signal data is sent to a subsequent baseband processingmodule. For the downlink, the baseband processing module in the basebandunit sends a baseband signal to a compressor, the baseband signal iscompressed by the compressor and subsequently sent to the radio remoteunit over the data transmission link, a decompressor in the radio remoteunit decompresses the received compressed signal data and sends thedecompressed signal data to a digital-to-analog converter where thedecompressed signal data is converted into a wireless signal andsubsequently sent by a transmitter. A method for compressing signal dataaccording to an embodiment of the present invention may be implementedin the compressors in the radio remote unit and the baseband unit, and amethod for decompressing compressed signal data according to anembodiment of the present invention may be implemented either in thedecompressor in the radio remote unit and may also be implemented in thedecompressor in the baseband unit.

FIG. 3 shows a block diagram of an information acquisition andprocessing system according to an embodiment of the present invention. Asignal acquired by a sensor sub-system is converted into signal data byan analog-to-digital converter, a compressor compresses the signal data,the compressed signal data is sent to a storage device via a storagechannel or a communication channel, the compressed signal data in thestorage device is decompressed by a decompressor, and then thedecompressed signal data is delivered to a signal processor forprocessing. A method for compressing signal data according to anembodiment of the present invention may be implemented in thecompressor, and a method for decompressing compressed signal dataaccording to an embodiment of the present invention may be implementedin the decompressor.

FIG. 4 shows a method for compressing signal data according to anembodiment of the present invention. The method comprises: in operationS401, obtaining signal data; in operation S402, determining blocklengths of a plurality of data blocks into which the signal data aredivided and exponents of the data blocks; in operation S403, forming amantissa sequence of a data block by using the exponent to compresssignal data contained in the data block; in operation S404, forming acompressed data block from the block length, the exponent and themantissa sequence of the data block.

The signal data obtained in operation S401 is generated by ananalog-to-digital converter and stored in a buffer in advance.

FIG. 5 shows a flowchart of determining block lengths of a plurality ofdata blocks into which the signal data are divided and determiningexponents of the data blocks, according to an embodiment of the presentinvention.

In operation S501, N consecutive signal data and a parameter m areinputted, wherein m is an arbitrary integer that can be exactly dividedby N.

In operation S502, the N signal data are sequentially divided into N/mdata blocks B₁, B₂, . . . B_(k) with a size of m.

In operation S503, an exponent of a data block is calculated accordingto exponents of signal data contained in the data block, wherein E(B) isdefined as an exponent of a data block B.

${E(B)} = {\min\limits_{d_{j} \in B}\left( {{\mathbb{e}}\left( d_{j} \right)} \right)}$wherein e(d_(j)) denotes an exponent of a signal data d_(j), and isdefined as the number of consecutive bits counting rightward from thenext bit of a sign bit of signal data d_(j), each of the consecutivebits having a value identical to the numeric value of this sign bit.

In operation S504, merging gains G of every two adjacent data blocks arecalculated. Specifically, a merging gain of two adjacent data blocks iscalculated according to the exponents, the bit numbers of block lengthtokens, the bit numbers of the exponent tokens, and the block lengths ofthe two adjacent data blocks. First of all, compression amounts v(B_(i))and v(B_(i+1)) of two adjacent data blocks B_(i) and B_(i+1) arecalculated respectively. Then, compression amount v(B_(i)∪B_(i+1)) of anew data block generated by merging the two adjacent data blocks B_(i)and B_(i+1) is calculated, and a merging gain of the two adjacent datablocks B_(i) and B_(i+1) isG_(i,i+1)=v(B_(i)∪B_(i+1))−(v(B_(i))+v(B_(i+1))). For a given data blockB, its compression amount v(B) is calculated asv(B)=E(B)·|B|−TokenSize<|B|>−TokenSize<E(B)>, wherein |B| denotes ablock length of the data block B, namely the number of signal data beingcontained; TokenSize(B) denotes the bit number of the length token ofthe data block B, and TokenSize<E(B)> denotes the bit number of theexponent E(B) token of the data block B. For example, if it is specifiedin advance that the length token and exponent token of the data block Bare denoted by 3-bit binary numbers, then both TokenSize<|B|> andTokenSize<E(B)> are 3.

In operation S505, merging gains of every two adjacent data blocks arecompared so as to obtain a maximum merging gain. In operation S506, itis determined whether or not the maximum merging gain is larger than 0.If yes, two adjacent data blocks corresponding to the maximum merginggain are merged in operation S507, and then the flow returns tooperation S504. If not, i.e., the maximum merging gain is less than orequal to 0, then block lengths of data blocks into which signal data aredivided are determined according to the last merging result in operationS508. For example, for 32 signal data, if the last merging result is 8,4, 6, 4, 2, 8, it indicates that the 32 signal data is sequentiallydivided into 6 data blocks, wherein a block length of the first datablock is 8, i.e., containing 8 signal data; the second data blockcontains 4 signal data, and so on.

FIG. 6 shows a flowchart of determining block lengths of a plurality ofdata blocks into which the signal data are divided and exponents of thedata blocks, according to another embodiment of the present invention.In operation S601, N consecutive signal data d_(j) are inputted. Inoperation S602, exponents e(d_(j)) of the N consecutive signal datad_(j) (j=1, . . . , N) are calculated, wherein the exponent e(d_(j)) isdefined as the number of consecutive bits counting rightward from thenext bit of a sign bit of signal data d_(j), each of the consecutivebits having a value identical to a numeric value of this sign bit. Inoperation S603, 1 is assigned to j. In operation S604, the exponentse(d_(j)) and e(d_(j+1)) of two adjacent signal data are compared; if|e(d_(j))−e(d_(j+1))|≦a given threshold, then the two adjacent signaldata d_(j) and d_(j+1) is merged. In operation S605, j=j+1. In operationS606, it is determined whether or not j is equal to N. If not, the flowreturns to operation S604. If yes, then in operation S607, block lengthsof a plurality of data blocks into which the signal data are divided andthe exponents of the data blocks are determined according to the lastmerging result, wherein E(B) is defined as an exponent of a data blockB.

${E(B)} = {\min\limits_{d_{j} \in B}\left( {{\mathbb{e}}\left( d_{j} \right)} \right)}$

Then in operation S403 of FIG. 4, signal data contained in a data blockis compressed using the exponent, so as to form a mantissa sequence ofthe data block. Specifically, the number of bits by which the signaldata contained in the data block is compressed is determined by theexponent of the data block, i.e., the number of bits reduced bycompressing the signal data contained in the data block is equal to theexponent of the data block. The compressed data block forms a mantissasequence of the data block. For example, the exponent E(B) of a datablock B is equal to 4, then each signal data contained in the data blockis compressed by 4 bits from the next bit of its sign bit, whereby amantissa sequence M(B) of the data block B is obtained. FIG. 7 shows anexample of generating a mantissa sequence and a compressed data blockaccording to an embodiment of the present invention, wherein the datablock B₁ consists of signal data d₁, d₂, d₃ and d₄, the block lengthL(B₁) of the data block is equal to 4, and the exponent E(B₁) of thedata block is equal to 4. The 4 signal data contained in the data blockB₁ are compressed wherein the signal data d₁ is compressed by 4 bitsstarting from the next bit of the sign bit, i.e., “00000” is compressedinto “0”; the signal data d₂ is compressed by 4 bits starting from thenext bit of the sign bit, i.e., “0000” is all reduced; the signal datad₃ is compressed by 4 bits starting from the next bit of the sign bit,i.e., “111111” is compressed into “11”; the signal data d₄ is compressedby 4 bits starting from the next bit of the sign bit, i.e., “00000” iscompressed into “0”; and finally the mantissa sequence M(B₁) isobtained.

In operation S404, a compressed data block is formed by using the blocklength, the exponent and the mantissa sequence of the data block.Specifically, the block length of the data block is converted into abinary block length token, and the exponent of the data block isconverted into a binary exponent token. Regarding the example shown inFIG. 7, for example, supposing that the block length of the data blockB₁ is equal to 4, and the exponent E(B₁) of the data block B₁ is equalto 4 and if it is specified in advance that the length token and theexponent token of the data block B₁ are denoted by 3-bit binary numbers,then the block length token of the data block B₁ is 100, the exponenttoken is 100. The 3-bit length token (100) and the 3-bit exponent token(100) are added before the mantissa sequence M(B₁), thereby forming acompressed data block C(B₁) from the length token, the exponent tokenand the mantissa sequence. By constructing a variable-length data blockadapted to dynamic characteristics of signal data, the method forcompressing signal data according to embodiments of the presentinvention make compression of signal data more robust, therebyincreasing the compression ratio of signal data.

FIG. 8 shows a method for decompressing compressed signal data accordingto an embodiment of the present invention. In operation S801, compressedsignal data is obtained. In operation S802, a block length and anexponent of a data block are obtained from the compressed signal data.In operation S803, a mantissa sequence of the data block is obtainedaccording to the block length and the exponent of the data block. Inoperation S804, original signal data corresponding to the data block isrestored by using the mantissa sequence and the exponent.

Decompression of signal data is a reverse process of compression ofsignal data, wherein the obtaining a block length and an exponent of adata block from the compressed signal data may comprise: extracting alength token and an exponent token from the compressed signal dataaccording to a predetermined bit number; converting the length tokeninto a block length of a data block; and converting the exponent tokeninto an exponent of the data block.

The obtaining a mantissa sequence of the data block according to theblock length and the exponent of the data block may comprise:determining the number of bits by which each signal data contained inthe data block is compressed, according to the exponent; determining alength of the mantissa sequence according to the block length of thedata block and the number of bits by which the data block is compressed;and obtaining the mantissa sequence from the compressed signal dataaccording to the length of the mantissa sequence.

Please refer to the description of the compression method fordefinitions of a block length, an exponent and a mantissa sequence of adata block and specific implementation details in the decompressionmethod, which are not detailed here.

Based on the same inventive concept, the present invention proposes anapparatus for compressing signal data and an apparatus for decompressingcompressed signal data. FIG. 9 shows an apparatus 900 for compressingsignal data according to an embodiment of the present invention. Theapparatus 900 comprises: an obtainment module 901 configured to obtainsignal data; a block length and exponent determination module 902configured to determine block lengths of a plurality of data blocks intowhich the signal data are divided and to determine exponents of the datablocks; a mantissa sequence formation module 903 configured to form amantissa sequence of a data block by using the exponent of the datablock to compress signal data contained in the data block; and acompressed data block formation module 904 configured to form acompressed data block by using the block length, the exponent and themantissa sequence of the data block.

According to the embodiments of the present invention, the block lengthand exponent determination module may comprise:

an initial data block division module configured to initially divide thesignal data into a plurality of data blocks;

an exponent calculation module configured to calculate an exponent of adata block according to exponents of signal data contained in the datablock, wherein E(B) is defined as the exponent of a data block B,

${E(B)} = {\min\limits_{d_{j} \in B}\left( {{\mathbb{e}}\left( d_{j} \right)} \right)}$

wherein e(d_(j)) denotes an exponent of signal data d_(j), and isdefined as the number of consecutive bits counting rightward from thenext bit of a sign bit of signal data d_(j), each of consecutive bitshaving a value identical to a numeric value of this sign bit;

a merging gain calculation module configured to calculate a merging gainof two adjacent data blocks according to the exponents, the bit numbersof block length tokens, the bit numbers of exponent tokens, and theblock lengths of the two adjacent data blocks;

a merging gain comparison module configured to compare the merging gainsso as to obtain a maximum merging gain;

a determination module configured to determine whether or not themaximum merging gain is larger than 0;

a merging module configured to merge two adjacent data blockscorresponding to the maximum merging gain, in the event the maximummerging gain is larger than 0;

a block length determination module configured to determine blocklengths of a plurality of data blocks into which the signal data aredivided according to the last merging result, in the event the maximummerging gain is not larger than 0.

According to the embodiments of the present invention, the mantissasequence formation module is configured to compress signal datacontained in the data block from the next bit of their respective signbits, wherein the number of compressed bits is determined by theexponent of the data block.

According to the embodiments of the present invention, the compresseddata block formation module is configured to form a block length tokenfrom the block length of the data block according to a predetermined bitnumber; form an exponent token from the exponent of the data blockaccording to a predetermined bit number; and combine the block lengthtoken, the exponent token and the mantissa sequence into the compresseddata block in a high-to-low bit order.

According to the embodiments of the present invention, the block lengthtoken is a binary code generated by converting the block length of thedata block according to a predetermined bit number, and the exponenttoken is a binary code generated by converting the exponent of the datablock according to a predetermined bit number.

Please refer to the description of the compression method fordefinitions of a block length, an exponent and a mantissa sequence of adata block and specific implementation details in the apparatus 900,which are not detailed here.

FIG. 10 shows an apparatus 1000 for decompressing signal data accordingto an embodiment of the present invention. The apparatus 1000 maycomprise: an obtainment module 1001 configured to obtain compressedsignal data; a block length and exponent obtainment module 1002configured to obtain a block length and an exponent of a data block fromthe compressed signal data; a mantissa sequence obtainment module 1003configured to obtain a mantissa sequence of the data block according tothe block length and the exponent of the data block; and a signal datarestoration module 1004 configured to restore original signal datacorresponding to the data block by using the mantissa sequence and theexponent.

According to the embodiments of the present invention, the block lengthand exponent obtainment module is configured to: extract a length tokenand an exponent token from the compressed signal data according to apredetermined bit number; convert the length token into a block lengthof the data block; and convert the exponent token into an exponent ofthe data block.

According to the embodiments of the present invention, the mantissasequence obtainment module is configured to: determine the bit number bywhich each signal data contained in the data block is compressed,according to the exponent; determine a length of the mantissa sequenceaccording to the block length of the data block and the bit number bywhich the data block is compressed; and obtain the mantissa sequencefrom the compressed signal data according to the length of the mantissasequence.

The apparatus 900 for compressing signal data and the apparatus 1000 fordecompressing signal data according to the embodiments of the presentinvention may be implemented as the compressor and the decompressor inthe baseband unit and the radio remote unit in the base transceiversystem as shown in FIG. 2, respectively, or implemented as thecompressor and the decompressor in the information acquisition andprocessing system as shown in FIG. 3, respectively.

Please refer to the description of the compression method fordefinitions of a block length, an exponent and a mantissa sequence of adata block and specific implementation details in the apparatus 1000,which are not detailed here.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, a program segment,or a portion of codes, comprising one or more executable instructionsfor implementing the specified logical function(s). It should also benoted that, in some alternative implementations, the functions noted inthe block may occur out of the order noted in the figures. For example,two blocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

The invention claimed is:
 1. A method for compressing signal data, themethod comprising: obtaining signal data; determining block lengths of aplurality of data blocks into which the signal data are divided anddetermining exponents of the data blocks; forming a mantissa sequence ofa data block by using the exponent of the data block to compress signaldata contained in the data block; and forming a compressed data blockfrom the block length, the exponent and the mantissa sequence of thedata block.
 2. The method according to claim 1, wherein the determiningblock lengths of a plurality of data blocks into which the signal dataare divided and exponents of the data blocks comprises: initiallydividing the signal data into a plurality of data blocks; calculatingthe exponent of a data block according to exponents of signal datacontained in the data block, wherein E(B) is defined as an exponent ofthe data block B,${E(B)} = {\min\limits_{d_{j} \in B}\left( {{\mathbb{e}}\left( d_{j} \right)} \right)}$wherein e(d_(j)) denotes an exponent of signal data dj, and is definedas the number of consecutive bits counting rightwards from the next bitof a sign bit of the signal data dj, each of the consecutive bits havinga value identical to a numeric value of the sign bit; calculating amerging gain of two adjacent data blocks according to the exponents ofthe two adjacent data blocks, bit numbers of block length tokens, bitnumbers of exponent tokens, and the block lengths; comparing the merginggains so as to obtain a maximum merging gain; determining whether themaximum merging gain is larger than 0; merging two adjacent data blockscorresponding to the maximum merging gain and repeating the calculatinga merging gain of two adjacent data blocks, in the event that themaximum merging gain is larger than 0; determining the block lengths ofa plurality of data blocks into which the signal data are dividedaccording to a last merging result, in the event that the maximummerging gain is not larger than
 0. 3. The method according to claim 1,wherein the forming a mantissa sequence of the data block by using theexponent of the data block to compress signal data contained in the datablock comprises: compressing signal data contained in the data blockfrom the next bit of a sign bit, wherein the number of bits by which thesignal data is compressed are determined by the exponent of the datablock, and the compressed data block forms a mantissa sequence of thedata block.
 4. The method according to claim 3, wherein the forming acompressed data block from the block length, the exponent and themantissa sequence of the data block comprises: generating a block lengthtoken from the block length of the data block according to apredetermined bit number; generating an exponent token from the exponentof the data block according to a predetermined bit number; combining theblock length token, the exponent token and the mantissa sequence into acompressed data block in a high-to-low bit order.
 5. The methodaccording to claim 4, wherein the block length token is generated byperforming binary coding to the block length of the data block accordingto a predetermined bit number, and the exponent token is generated byperforming binary coding to the exponent of the data block according toa predetermined bit number.
 6. A method for decompressing compressedsignal data, comprising: obtaining compressed signal data; obtaining ablock length and an exponent of a data block from the compressed signaldata; obtaining a mantissa sequence of the data block according to theblock length and the exponent of the data block; and restoring originalsignal data corresponding to the data block by using the mantissasequence and the exponent.
 7. The method according to claim 6, whereinthe obtaining a block length and an exponent of a data block from thecompressed signal data comprises: extracting a length token and anexponent token from the compressed signal data according to apredetermined bit number; converting the length token into a blocklength of the data block; and converting the exponent token into anexponent of the data block.
 8. The method according to claim 7, whereinthe obtaining a mantissa sequence of the data block according to theblock length and the exponent of the data block comprises: determiningthe number of bits by which each signal data contained in the data blockis compressed, according to the exponent; determining a length of amantissa sequence according to the block length of the data block andthe number of bits by which the data block is compressed; and obtainingthe mantissa sequence from the compressed signal data according to thelength of the mantissa sequence.